[Production of noninfectious virions of the Rous sarcoma virus by virogenic hamster cells]

Noninfectious virions morphologically identical with avian type C virus virions were produced in Rous sarcoma virus-transformed virogenic hamster cells. The population of the virions contained the major internal protein of avian oncornavirus. It is assumed that production of defective RSV virions occurred in the cells. The major internal protein of avian oncornaviruses was found to be incorporated into the virions containing in their membrane interspecies antigens of hamster oncornavirus produced spontaneously in the system under study. Thus, phenotypic mixing of avian and animal type C viruses in mammalian cells has first been observed.